# HG changeset patch
# User Jim Hague <jim.hague@acm.org>
# Date 1330945557 0
# Node ID 811151d3ae7329118c592e8f99e6c05cba162c8b
# Parent  f73a0193beb8445c7dbe1d9911d785045bdd7863
Improve first line extractor. Only output at most two lines.

I've met .abc files where every line is a continuation.

diff -r f73a0193beb8 -r 811151d3ae73 abcfirstline.py
--- a/abcfirstline.py	Mon Mar 05 11:03:15 2012 +0000
+++ b/abcfirstline.py	Mon Mar 05 11:05:57 2012 +0000
@@ -7,17 +7,28 @@
 import sys
 
 def process(inf):
+    continued = False
     print "X:1"
     for line in inf:
         line = line.strip()
+        # If it is empty or starts "%", ignore it.
+        if len(line) == 0 or line[0] == "%":
+            continue
+
+        # Is it a header line? I.e. does it start LETTER COLON?
+        # If so, output only ones we need.
         start = line[:2]
-        if len(start) > 1 and start[0] != "|" and start[1] == ":":
+        if len(start) > 1 and start[1] == ":" and start[0].isalpha():
             if start[0] in ["M", "K", "L"]:
                 print line
-        elif start[0] != "%":
+        # Output line. If it is a continuation, output at most one
+        # continuation.
+        else:
             print line
-            if line[-1] != "\\":
+            if continued or line[-1] != "\\":
                 break
+            else:
+                continued = True
 
 if len(sys.argv) > 1:
     for arg in sys.argv[1:]: